TELEOLOGY

Intro: According to Aristotle, everything that exists has a final cause, or purpose – what in Greek is called a telos. In other words, everything in nature exists to fulfil a goal.

EXPLAINING things in terms of their purposes was not unusual among classical Greek philosophers, but today it stands at odds with our modern, scientific understanding of the world. To our modern eyes it is quite normal to describe a man-made object, such as a tool, in terms of its function or purpose. A hammer, for example, exists for the purpose of pounding in nails. But this is an extrinsic purpose, one that is imposed upon it from the outside. What Aristotle proposed was that everything, including everything in the natural world, has an intrinsic purpose: that is, each thing exists in order to achieve its own ends – its internal purpose. For example, a seed’s purpose is to germinate and become a plant, and trees exist in order to produce fruit.

For Aristotle, it is not only living things that exist for a purpose. Rain falls in order to moisten the ground and enable plants to grow. It is the rain’s telos to water the earth, and the plants’ telos to grow. Their purpose or goal is the reason they have come into being.

More in line with our modern thinking is the Atomists’ assertion that natural things do not have an intrinsic purpose or “final cause”: instead, their existence is the cause of other things. Rain does not fall in order to water the plants; rather, the plants use the moisture that happens to have been provided by the rainfall.

. The Unfolding World

For Aristotle, the essential property of a seed is its ability to grow. That is also its intrinsic purpose: it exists to become a plant, which, in turn, exists in order to produce seeds. Living things are therefore characterised by their tendency to move or change, and to reproduce. And, since all terrestrial things are imperfect and impermanent, beings not only grow, but also eventually perish and decay.

. Causation

Aristotle’s theory of causation is based on his idea that everything has four causes. What we usually think of as a cause – that which makes a thing happen – is what Aristotle calls an “efficient cause”. For example, a person who pushes a rock downhill is the efficient cause of the rock’s movement. The purpose, or “final cause”, of its movement – why it goes downwards instead of up or sideways – is that it is seeking the centre of the Earth. The final cause of the action of pushing the rock is to see how far it will roll. The rock’s movement is also determined by formal and material causes.

Efficient Cause – in this example, the efficient cause is the person who pushes the rock. The rock moves because of the person’s actions.

Material Cause – This is the rock’s physical composition. The rock is made of earth, and so, because earthy things seek the centre of the Earth, it moves downwards.

Formal Cause – The shape of the rock’s trajectory is determined by the landscape. The rock’s rolling and bouncing are caused by the slopes and bumps of the hill.

Final Cause – The rock comes to rest when it reaches the closest it can get to the centre of the Earth – the bottom of the hill.

THE UNMOVED MOVER

Aristotle’s universe had no beginning, but he believed that something must have set the heavenly bodies in motion, since everything is caused by something else. However, this raises two questions: What caused that cause, and what moved the mover of the Universe? Aristotle proposed the idea of a first cause, an “unmoved mover”, responsible for all the motion in the universe.